Study of the Preparation and Quality of Gastrodia elata with Different Drying Processes

The objective of this study was to evaluate the effects of different drying methods on the quality of fresh Gastrodia elata after drying and processing. Four drying methods, including natural air drying, hot air drying, vacuum freeze drying, and vacuum microwave drying, and two pre-treatment methods (unprocessed and steam processed) were used. Scanning electron microscopy was used to observe the microstructure of dried Gastrodia elata , and high-performance liquid chromatography was used to measure the content of eight functional components such as gastrodin, p-hydroxybenzyl alcohol etc. The in vitro antioxidant and hypotensive experiments were also conducted. The results showed that pre-treatment methods and different drying methods had a significant effect on the morphology and functional component content of Gastrodia elata. The steam processed-vacuum freeze drying (PGB-CFD) treatment group had the highest functional component content, with a total content of 42.71 mg/g. The unprocessed-vacuum freeze drying (NGB-CFD) treatment group had the highest antioxidant capacity, while the steam processed-vacuum freeze drying (PGB-CFD) treatment group had the highest ACE enzyme inhibition rate. This study provides reference methods and basic data for the further processing of fresh Gastrodia elata.